Dental handpieces



Aug. 28, 1962 M. sTAuN'r DENTAL HANDPIECES 7 Sheets-Sheet l Filed Aug.13, 1959 IN VEN TOR. Marinz Szcmrz z's arrzey Aug. 28, 1962 M. s'rAUN'rDENTAL HANDPIECES '7 Sheets-Sheet 2 Filed Aug. 13, 1959 |||||||IlJflllllulllllll 9m@ www www Wsw ab NN @NEN PHIHIIIIIIIIH IWWN.

.III ...n

A ubl Il,

INVENTOR. Mclzzz S'auzzi BY is zqorney Aug. 28, 1962 M. sTAuNT 3,050,856

DENTAL HANDPIECES Filed Aug. 1s, 195s 7 sheets-sheet s 244 gl f243 231IN V EN TOR.

Muffin stam? ug. 28, 1962 M. sTAUN'r 3,050,856

DENTAL HANDPIECES Filed Aug. 13, 1959 7 Sheets-Sheet 4 FIGT 12 FIGT 1 8FULL ceo WN PREPA RAT/ous 3 SURFACE PREPAQAT/aus 6D 50 5o 4a 4a .S so ao20 2o 7D 70 0 a 12am,

E. E NLS P. Ms FI G1 19 FIST 20 740 CAV/TY PREPARATION M wfwm/VWm/mM/w Lw90 56 SOqA/WVVLA/wA/vvvvm .3g 60 l f MSOMMM/WVWVWWMW/wvwl/mf 4a E E 2a9950 www 0 2000 41200 6000 70400 72000 Vl R'q T 0N No Coo Zani 1.5 Lbs.Press. Wafer Caaled l5 Lbs, Press,

FIG? 2 Z FI ZZ 4 y (1 H v )/I. Ir" A w @(@l MI /I d l A, a!

Aug. 28, 1962 M. sTAUNT DENTAL HANDPIECES 7 Sheets-Sheet 5 Filed Aug.13, 1959 7 Sheets-Sheet 6 Filed Aug. 13, 1959 www mwN

1N V EN TOR. Mara?? 5i/m @eM/KM@ y Aug- 28, 1962 M. sTAUNT 3,050,856

DENTAL HANDPIECES Filed Aug. 13, 1959 '7 Sheets-Sheet 7 M IN V EN TORmi??? ,Sfax/275,

DM/wwf strasse Patented Aug. 2S, 1962 ice 3,050,856 DENTAL HANDPIECEShlartin Staunt, Des Plaines, lll. (4439 W. Rice St., Chicago, El.) FiledAug. 13, 1959, Ser. No. 833,412 28 Claims. (Ci. 32-26) The presentinvention relates to dental handpieces, and is particularly concernedwith the provision of improved dental handpieces adapted to be operatedat higher rotative speeds.

The present application is a my prior application on Dental 494,607,tiled March 16, 1955, 1959, and now abandoned.

One of the objects of the invention is the provision of improved dentalhandpieces adapted to be operated at rotative speeds in excess of 25,060rpm. and which will run cooler and more smoothly, and also more quietlythan the devices of the prior art.

Another object of the invention is the provision of improved dentalhandpieces with higher operating speeds which will enable the dentiststo accomplish their work with greater ease and speed, reducing thecavity preparation time to a fraction of that formerly required by thedevices of the prior art.

Another object of the invention is the provision of improved dentalhandpieces which may be operated at lighter pressures and `whichproduces less vibration and reduces frictional heat, all of whichcontribute to the result of causing less trauma to the patient.

Another object of the invention is the provision of improved handpieceshaving improved bearings which are adapte-:l to take the lateral andaxial thrust that is placed upon them by use of the handpiece, and whichoperates more smoothly and with less vibration and noise, and at greaterspeeds than the devices of the prior art.

Another object of the invention is the provision of an improvedhandpiece assembly which is adapted to be used with the burs and contraangles and other attachments of the prior art, but which is also adaptedto be used with a plurality of high speed attachments, any one of whichis quickly substituted for another in the assembly, thereby enabling theuser to have available a plurality of dilferent handpiece assemblies bymerely purchasing one handpiece and the additional attachments.

Another object of the invention is the provision of an improved dentalhandpiece and attachments of the antifriction type adapted to beoperated at much higher weeds than the devices of the proior yart due tothe use of special anti-friction bearings mounted in the most simplemanner, which involves the use of `a minimum number of parts and aminimum number of machine operations.

Another object of the invention is the provision of an improved dentalhandpiece of the ball bearing type, in

continuation-impart of Hand Pieces, Ser. No. and allowed March 9,

which the entire spindle is removable with its ball bearv ings by merelyunscrewing a cap at the pulley end, which holds the spindle and itsadjacent ball bearing in the hand piece, so that the entire spindle andthe sheath assembly may be cleaned and sterilized separately.

Another object of the invention is the provision of improved sleeveattachments for handpieces of the class described and the provision ofimproved lubricating arrangements for wrist joint pulleys and theprovision of an improved high speed driving and elbow joint attachmentfor such handpieces.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which similarcharacters of reference indicate similar parts throughout the severalviews.

Referring to the drawings, of which there are sevenl sheets accompanyingthe specication,

FIG. l is a side elevational view of a handpiece embodying the inventionin partial section along a plane located in the axis of the spindle,showing the details of construction;

2 is a larger fragmentary view taken on the same piane and showing thetool end of the handpiece in greaterV detail;

FIG. 3 is a side elevational view in partial section of the sheath ofthe handpiece of FIGS. 1 and 2;

FIG. 4 is a fragmentary side elevational view of the tool end of thesheath of FIG. 3;

FG. 5 is a fragmentary side elevational View of the other end of thesheath, showing its mode of attachment to the handpiece; Y

FIG. 6 is a fragmentary sectional view takenV on a plane passing throughthe axis of the spindle, showing on a larger scale the details of theattachment of the sheath to the handpiece;

FiG. 7 is a sectional view taken on the plane of the line 7-7 of FiG. 6,looking in the direction of the arrows;

FiG. 8 is a sectional view taken on the plane of the line 8 8 of FIG. 3,looking in the direction of the arows;

FiG. 9 is a fragmentary elevational View in partial section on the planeof the axis of the shaft, showing the conversion sheath which may beemployed on the handpiece of FIG. l for converting the variousattachments to long sheath models;

FiG. 10 is a sectional view taken on the plane of the line itl-iii ofFIG. 9, looking in the direction of the arrows;

FIG. ll is a fragmentary side elevational view ofthe driving end of theconversion sheath, showing an alter-' native form of ball bearings;

FIG. l2 is a fragmentary sectional view taken through the wrist jointand pulleys, by means of whichthe handpiece and its driving belt aresupported.

FIG. 13 is a sectional view taken on the plane of the line 13-13 of FIG.l2, looking in the direction of the arrows;

FiG. 14 is a fragmentary elevational view taken on the plane of the line14-14 of FIG. l2, looking in the direction of the arrows;

l5 is a sectional view taken on the plane of the line 15-15 of FIG. l2,looking in the direction of the arrows;

FIG. 16 is a sectional View taken on the plane of the line 16-16 of FIG.l2, looking in the direction of the arrows;

FIG. 17 is a reproduction of a graph showing reduction in time used forfull crown preparation at higher speeds;

FiG. 18 is a reproduction of a graph showing reduction in time used forthree surface preparations at higher speeds;

FIG. 19 is a reproduction of a graph showing temperature rise at higherspeeds, with and without use of water coolant;

FIG. 20 is a reproduction of vibration curves on an oscilloscope ofhandpieces operating at various rotative speeds;

FIG. 21 is a fragmentary enlarged sectional view of the ball bearing'assembly used at the right end of FIG. 1;

FIG. '22 is la fragmentary sectional view of the contra angle structureat the left end of FIG. 9; v

FIG. l23 is a fragmentary sectional view of the dental plugger which maybe attached at the left end of FIG. 9;

FIG. 24 is a view similar to FIG. 1, showing a modiings of an improved-type which are removable with the spindle; l

FIG. is a continuation of the right end of lEIG. 24 on the same scale,showing this improved construction;

FIG. 26 is a side elevational View of the removable spindle unit withits ball lbearing and threaded collar;

FIG. 27 is a sectional View taken on the plane deiined by the axes ofthe two shafts, showing an improved ball bearing contra angle which maybe employed as an attachment;

FIG. 28 is 4a fragmentary sectional view, showing the air and waternozzles as viewed from the bottom of FIG. 27;

FIG. 29 is an axial sectional view taken through the long attachmentsleeve which may be used with the handpiece of FIGS. 24 and 25;

FIG. 30 is an axial sectional view, showing the short attachment sleevehaving a shaft that is adapted to be held by the chuck of FIG. 24;

VFIG. 31 is a fragmentary sectional view of a high speed drive `geararrangement embodied in an elbow joint and adapted to be employed withthe attachments of the present handpiece; v

FIG. 32 is a fragmentary elevational View of the Wrist joint, similar toFIG. 1, but including various improvements;

FIG. 33 is a lfragmentary sectional view, similar to FIG. 12, butincluding the additional improvements of FIG. 32;

FIG. 34 Vis a fragmentary sectional view, ltaken on the axis of a shaft,showing the ball bearing assembly which is preferably employed in all ofthe anti-friction bearing assemblies used in Ithe present lhandpieces;

FIG. 35 is a side elevational View of the ball retainer;

FIG. 36 is an end elevational View of one of the ball bearingassemblies, taken from the left end of FIG. 34;

FIG. 37 is a .similar end elevational view of the ball bearing assembly,taken from the right end of FIG. 34;

FIG. 38 is a sectional view taken on the plane of the line 38-38 of FIG.37, looking in ythe direction of the arrows. l

The wrist joint 'assembly 21 preferably includes the hinge member 22,having an axially projecting shaft 23,

which is rotatably `mounted in la bore 24 in the elbow `by a rotatabletop stop member 32, which is mounted on *the squared end 33 of shaft 23,by means of a squared aperture, so that it rotates with the shaft 23.

Stop member 32 yalso acts as an end thrust bearing and is secured bymeans of a screw vbolt 34, threaded into a threaded bore 35.

Pin 30 and shoulder 31 prevent the wrist joint from making more than onerevolution on the shaft 23 and prevent the belt from becoming twisted.

At itsother end the elbow body26 is formed with the integral bearinghousing 36, which comprises `a cylindrical tbody extending atsubstantially right angles tothe shaft 23 and having an outer threadedportion 37 at its rear end. Y

This threaded portion is adapted to receive the in-Y rternally lthreadedcollar 38, which has a cylindrical ange 39 internally threaded, and anend flange 40 adapted to engage the outer ball bearing race 41 andsecure it in a counterbore 42 against an annular shoulder 43.

The end ange of the collar hasa central bore 44 which has a clearancewith respect to the spindle 45 and its spacing sleeve 46 so that thereis no contact between the rotating spindle and the collar 38. Y

Collar 38 has an annular shoulder at 47 for engaging the side of therace 41 and the end flange 49 has a clearance at 48 beside the races ofthe ball bearing to avoidV` contact between the collar 318 and the innerrace 49.

The races of the ball bearing assembly, indicated atv 41 and 49,comprise hardened steel members; and the inner race 49 comprises yanannular member having an plane end surfaces and an annular groove ofpartially,l

circular cross section on its inner cylindrical surface for receivingthe balls 54, sufficient of -which are provided in the grooves to extendallV the way around the periphery of the grooves with a spacing betweenthe balls.

The balls 54 (FIG. 2l) may be mounted in a cage and` the outer race 41may be grooved to receive the oil seals 41a, which are held in place bysplit rings. The Seals have a clearance with respect to inner race 49.'

The cylindrical housing 36 has the enlarged bore 65 and a smallVcounterbore I66 and -a longerbore v67 in an integral tubular part 68.

The housing 36 has the reduced threaded portion 69 on its left end forreceiving the internallly threaded collar 70 which abuts Iagainst anannular shoulder 71 and is used .to secure the sleeve 72 of thehandpiece to the wrist joint housing 36.

Tubular part A68 has a lcylindrical outer surface 73; 'andthe sleeve 72has -a cylindrical bore 74 so that the sleeve may slide on the tube 68against an annular shoulder 75.

The sleeve 72 has a plane end 76 engaging the annular shoulder 75; andthe sleeve has a radially projecting annular ilange 77, which extendsinto the bore of collar 70 at the clearance 78, where the collar isunthreaded.

The collar 70V has a smaller counterbore 79 in its left end which isformed with an outer rounded sunface; and the bore 79 is adapted toreceive Athe sleeve 72, which has yan outer cylindrical surface Sil.

Collar 7i) has the inner shoulder y81 which draws the radial flange 77against shoulder 75. There is sufficient clearance ybetween the flange77 and the adjacent surfaces to permit the -sleeve 72 Ito rotate insidethe collar on the tube 68.

Referring to FIGS. 1 and y6, the sleeve 72 is provided with an annulargroove 82, which is bounded by two annular shoulders 83, 84, and 4by acylindrical surface 85 at the bottom of the groove.

This annular groove extends all the way around the sleeve 72, exceptthat sleeve 72 has an axially extending slot 86 extending into its endbeyond the groove 82, and defined by longitudinally extending edges 87,88 which extend lto the end 89 `of the groove 86, as shown in FIGS. 6and 7.V

This groove 86 provides a longitudinally extending slot into which alongitudinally extending lug 98, carried by the sheath 91 (FIG. 3), maybe moved in attaching the sheath.

The circumferential groove 82 about the end of sleeve 72 (FIG. 6)contains a resilient, partially cylindrical spring band 92, which hassufficient resiliency so that it` Thus the band 92 has the outer andinner cylindrical Y surfaces 95, 96 (FIG. v6); and its width is`suiicien-t to t in the groove S2, having plane edge surfaces 97, 98(FlG. 6).

Band 92 is of sullicient external diameter so that it is flush with theoutside of sleeve 72, or the band may project slightly beyond sleeve 72when it is secured in the cylindrical bore 99 of a rotatable actuatingmember 11M), which may be assembled by sliding member 10B onthe sleeve72 and band 92 until it overlaps the sleeve 72 and the sheath 91.

The actuating member 19t) is xedly secured to the band 92 so that it maybe used to rotate band 92 in groove 86. Band 92 may have a pair ofoppositely located through bores 101, into which the adjacent parts ofthe member 191) may be forced with a center punch and brazed by a dropof brazing material.

Thus the band 92 is adapted to be rotated by the actuating member 1110,which is actually a tube having the external knurled surfaces 104, 105,separated by a relief 166 and tapering toward both edges.

The band 92 is shorter circumferentially at the groove 82, in which itis mounted, Ithan the adjacent portion of the sleeve 72, as will be seenin FIG. 7. Thus the ends of the band are at 93, 94, which are widerapart than the edges of the slot 87, 8S, and the edges of the groove 82,indicated by 83 and S4, are inwardly deformed at 197 and 168 in F15. 6,at a point which is spaced from the edge 87 ofthe slot S6.

This prevents band 92 from making a completeV rotation; but it mayrotate across the slot S6, that is, counterclockwise in FIG. 7, untilthe end 94 of the band 92 completely traverses the slot 26 and strikesthe stop 1%. This is the locked position of the Iband 92.

Band 92 may also rotate in the opposite direction until its end 93engages the stop 168, in which position the ends of the band 92 at 93and 94 will be located outwardly of the ends of the slot S5, which areindicated at S7 and SS. In other words, the band will be completely outof the slot S6 in its unlocked position.

Referring to FIG. 3, the sheath 91 comprises a tnbular metal memberhaving outer cylindrical surfaces at 1139 and a grooved gripping surface119, having a plurality of cylindrical knurled lands 111 separated bypartially circular grooves 112.

The grooves being circular makes them easy to keep clean, as foreignparticles do not stick in circular grooves, as they do in rectangularcorners. Y

At its right end, FIG. 3, the sheath 91 has an enlarged outercylindrical surface 113 and a plane end surface 114, from which thereprojects a partially cylindrical lug or locking extension 90, which isan integral part of the sheath 91.

Lug 99 is bounded at its edges by radially located plane surfaces 115and 116, which surfaces will be received between the edges S7 and 88 ofthe endwise slot 36 in the sleeve 72. In other words, the projectingextension on the end of the sheath 91 is complementary to the slot S6that is formed for it in the sleeve 72.

The external cylindrical surface 113 of lug 90 is the same size as theexternal surface Si) on sleeve 72, and lug 99 has an internal bore whichis the same size as the bore 67 in sleeve 72.

Lug 99 also has a peripherally extending shallow groove 117, which is ofthe same size and width as the groove 82 in the sleeve 72 in which theband 92 slides. The boundaries of groove 117 may be indicated by itsedges 33a and 84a, and its bottom 85a, to indicate that groove 117 inthe sheath 91 is merely a continuation of the groove S2 in the sleeve72, when the sheath has its lug 90 in the longitudinally open slot 86.

rThe end 118 of the sheath 91 (FIG. 3) is plane, fitting against the end119 of the sleeve 72.

Referring to PEG. 22, this is a fragmentary view showing the left end ofthe handpiece, when the sheath 91 is e Atripped with a high speed contraangle attachment. 'This contra angle includes the right angle housing391,

having rotating sleeve SSI-'2, receiving the shank of a bur 3553 orother tool, and retained by pivoted retainer 304.

The sleeve 302 is driven by bevel gears (not shown) in housing 3111, onegear being on shaft 395, which is rotatably mounted in tube 336,threaded in housing 361. rThe end of tube 366 has an annular head, withaxial teeth, drawn against similar teeth on the end of knee housing 309,by threaded collar 310. This housing 361 may be secured at any angle byrotating it in collar 310.

Shaft 305 has a gear 311 with axially beveled teeth pinned to it fordriving a similar gear 312 carried by shaft 313. Knee housing 309 isexternally threaded for collar 31@ and internally threaded to receivethreaded end 314 of extension 315 inf which shaft 313 rotates. Shaft 313carries a driven member having axial lugs 170:1, 171e to engage drivinglugs 170.

Referring to FIG. 23, this is a agmentary view showing the handpiecewhen equipped with a quickly rem0vable high speed dental plugger 321i.The dental plugger is attached to a similar sheath 91 in the same manneras the preceding contra angle. Its right angle housing contains a sleeve321 for sliding movement and lfor supporting the shank of a plugging or-tamping tool 322.

The shaft 3115 of this attachment carries an eccentric dog or hammerwhich engages a radial flange on sleeve 321 (not shown) and impartshammer blows to the sleeve 321 and tool 322. The rest 'of the structureis the same as the preceding one and bears similar numerals.

Any number of sheaths bearing attachments, of which these are examples,may be provided and quickly detached or attached by the user in a fewseconds. The drive by loosely engaging lugs 179, 171, and 17la, 171a, isfound to reduce vibration to a minimum at high speeds, as shown by thelower curves in FIG. 20.

The operation of these parts is as follows:

When the actuating member 166 is rotated until the band 92 slidesrotatably out of the 4shallow groove 117 in locking extension 99, thesheath 91 may be slid axially away from the sleeve 72 and detached. Theunlocking rotating motion of the band 92 is limited by edge 93 striking`stop 168.

With the parts in this position the same sheath or another sheath may beslid over the spindle and may have its lug 9i) slid endwise into theopen-ended slot 86, of the sleeve 72, until the end surfaces 119 ofsleeve 72 and 118 of sheath 91 are in engagement.

Then the edges and 116 of lug 90 will be engaging the edges 87 and 88 ofthe slot 86 in sleeve 72 to prevent rotation of the sheath ion thesleeve.

At -this time the shallow groove 117 in the sheath extension 90 willregister with the shallow groove 82 of the sleeve 72, and the lockingband 92 may be rotated by its actuating member 100, the band 92 slidingin its lpresent groove S2 and also across the lug 90 in the lgroove1117, until the end 94 of band 92 engages `stop 103. Then the band 92locks the extension lug 90 to the sleeve 72; `and it is also held inalignment by the inner surface 99 of actuating member 100.

The sheath 91 is also held -in accurateconcentc alignment with thesleeve 72 by being slidably mounted on the integral tubular part 68,which extends to the left in FIG. 1, from the housing 36 and is adaptedto ysupport the bearing assembly at the tool end of the handpiece.

The tube 68 has the outer cylindrical surface 73, previously described,engaging the inner bore 74 lin sleeve 72,

. and also engaging the inner bore 121 in sheath 91.

Thus the sheath 91 and sleeve 72 together constitute a rotatableexternal` handle on the handpiece, which, being rotatable on the tube68, permits the Wrist joint 25 to hang `downward when the sheath 91 issupported by the hand of the user.

The tube 68 is provided at its left end (FIG. 2) with a largercounterbore 122 for receiving fthe roller bearing assembly 120.

This roller bearing assembly comprises an outer tubular spense@ race123, having a cylindrical outerY surface 124 with a fric-A tional lit inthe counterbore 122.

The outer race -123 has an inner cylindrical vsurface 125 engaged by therollers 126, of which there are suiicient to extend all the way aroundthe inside of the bore 125, with a clearance between roller surfaces.

The rollers 126 are hardened steel members having the externalcylindrical surface 127 and plane end surface-s 128 at the end of aconcave tapered surface of revolution 129, forming an axial pin at eachend of the rol-ler.

The external race 123 is threaded internally at 131, 132

at each end. Each end is provided with a combined in-v ternal race andthrust collar 133, 134. Each thrust collar has an internal bore 135 witha clearance about the spindle 45.

Each collar 133 has an external cylindrical surface 136 which iscylindrical yand ush with the inner surface 124 of |the outer race 123.Y

Each collar has an outer threaded surface 137 which may be threaded intoIthe threaded bores 131, 132. Each collar has an -annular thrust surface138 lfor engaging the ends 128 =of the rollers 126.'

Each collar has an inwardly projecting tubular ange 139, iiush with theinner bore 135, and having its outer cylindrical surface 140 spaced fromthe concave outside 129 of each pin 136 on each roller 126. Thus lthereis no contact between the sides of pins i138 and the retaining flange139 which holds the rollers in the outer race 123.

The space between the inner bore 125 of the outer race 123 and thecylindrical surface 141 on spindle 45 is occupied by the rollers 126,whose cylindrical surfaces '127 rotatably support the spindle at itscylindrical surface 141 in the bore 125 of the outer race 123.

The cylindrical surface 141 has a heavy deposit of hard chromium platingto increase the bearing life greatly.

The spindle comprises a tubular metal member having the outercylindrical surface at its left end (FIG. 2) extending to the annularlshoulder 142 to the iight of the roller bearings. From this point thespindle is enlarged and has the outer cylindrical surface 143 providedwith -a clearance. 144 inside the bore 121 of the tube 68.

The spindle'is supported at its right end by the ball bearing assembly,Where the spindle has a reduced cylindrical surface 51; and the innerrace 49is held against shoulder 52 bya spacing tube 46 (FIG. 1), whichis engaged at its other end by the pulley 146.

Pulley 146 Ii-s mounted on a reduced cylindrical portion 147 of thespindle 45 and is held Aon this reduced portion 14-7 by a threadedbushing 148 having fa knurled head 149 with at sides for reception of awrench. n

The lbushing `14S has an annular surface 159 engaging the'pulley 146;and the lbushing has Ian external thread 151 on a reduced portion whichis threaded into -a threaded bore 152 in the spindle 45. y

The spindle has .a key 153 disposed in a keyway in the pulley 146 andthe spindle and preventing rotation of the pulley on the spindle. Thepulley is formed with a plurality of pheripheral grooves 154 and 155 ofdifferent diameter, separatedby radially extending flanges; and thegrooves are tapered for engaging a belt in the form of a cord whichengages the, sides of the pulley, `orrin some cases engages a curvedbottom ofthe pulley groove.

The pulley is concave at its inner side 156 so that it exi tends aboutthe coll-ar 38 and prevents the ingress of dirt yand moisture into thebore 44.

The bushing`148, which secures thel pulley on the spindle,l isalsoprovided with a threaded bore 157 for rel The knob 161 is ad-aptedto rotate the chuck rod 159'k in the-bushing 148, causing it to engagethecollet `actu- Vend 173 kwith beveled corners, and are intended to beused ating member 164- by means of it-s end 165. Converselyf-rictionallit in bore of the yspindle 45 to prevent whipping of this end oftherod; `and the end surface'165 or" the rod is partially spherical. Y

The spindle d5 is rotatably mounted at its left end by the rollerbearings and has the reduced cylindrical part which has a continuationof the bore 160 for housing a collet 167. The bore 16u has `afrusto-conicalsurface 168 at its end which communicates with a smallercounterbore 169; and the spindle has a pair of longitudinal drivingextensions 170, 171 comprising lugs extending longitudinally of thespindle and forming a continuation of the spindle wall from the bore169.

The lugs have ilat radially extending sides 172 and a flat for drivingsimilar lugs on a driven member 174 (FIG. 9), which driven member isadapted to drive a contra angle. The collet 167 comprises asubstantially cylindrical member having the external cylindricalsurfaces 175, 176 at each end and another cylindrical surface 17'7midway between the ends with reduced portions 178 and 179.

'Ille cylindrical sur-faces 175-177 fit in the bore`164l which guidesthe collet; and the collet is provided with a plurality of inwardlyextending slots 180 at each end and with an internalV bore 181- at eachend, said bore having a substantial'iitV withV the shank of a bur orother tool to be secured inthe collet. 1

a cylindrical member sliding'in the bore 1611, and havingV afrusto-conical kcavity 182 leading to a bore 183 forY receiving theconical'end 184 of the collet. j

The collet has a truste-conical end surface 185 at its outer endengaging in the truste-conical bore V168.

The operation of the collet is as'follo'ws: The collet bore 181 isalready a substantial lit on the shank of the -bur or other tool. Whenthe ,push rod is threaded clockwise, it moves this rodV 159 tothe left,pushing the collet actuating member 164,' and the conical surfaces 168and 182'cause a contraction of the ends of the collet by engaging theouter conical surfaces 185 and 184. Y

The slots V180 the shank; but upon moving the rod 159 in the oppositedirection, the collet springs backto non-gripping position. M The sheath91 has its working end provided with aA reducedv tapered portion 186,whichV has afurther tapered surface at 18.7 containing thebore 188,which houses the Y is gripped thereby while the external housing isrmountedy on tapered nose 186.

The sheath 91 has its tapered nose 1886 provided with a y longitudinallyextending lug projecting'from surface.

186beyond the annular shoulder1'91; and the lug 199 has a rounded end192 and parallell edges so that this sheath may receive the contra anglehousings as previously Y constructed. The lugv19il preventsthe rotationof the housing on the sheath. f

Referring to FIGS. 1 :and l2, these views show the wrist The hingemember 22 has al flattened end portion 193, which is Vpivotally mountedin a slot in a flat body 194 by means of a screw bolt 1,95'passjoint andits pulleys.

ing through the flattened end and threaded into' a threaded bore.

A pin 196 extends across the slot 197 and is adapted to engage a stopshoulder 198 or 199 on either of the. f

hinge members 22 or 200'. The second hinge member 213i? has itsflattened end 281k mounted slot 197 on screw contract and the colletresiliently .gripsk n 9 bolt 202 threaded into bore 203, Iboth of thesemountings being alike.

'I'he body 194 has a through bore 204 for receiving a shaft 205 forsupporting the pulleys 206, which are identical. Shaft 205 is held inbore 204 by a set screw 207 and projects laterally from each side of thebody 194.

Each end of the shaft is provided with a reduced cylindrical portion208, forming a groove, and bounded by annular shoulders 209 and 210. Aplurality of hardened steel cylindrical rollers 211 are mounted in saidgroove and inside the bore 212 in each pulley. Each pulley has a largerthreaded end bore 213 and 214, and a thrust bushing 215 is threaded ineach end of the pulley and provided with a plane thrust surface 216engaging the rounded ends of the rollers.

Each bushing has an annular iiange withva surface 217 seated against theend 218 of the pulley. Shaft 205 has a through bore with threads 219 ateach end for receiving the threaded shank 220 of a guard 221, comprisinga circular member carried by the threaded shank 220, and having aninwardly curved surface 222 carrying a cylindrical liange 223, whichoverhangs the edge 224 of the pulley.

The pulley has a round tapered groove 225 between the projecting edgeportions 224 and 226. The hinge member Zi is preferably provided with ananti-shock mounting, indicated at 227 in FlG. 12, for the purpose ofpreventing the transmission of vibration rom the engine through this acylindrical bore 229 at one end for receiving a rod carried by theengine mechanism and fitting in the bore 229. The rod 228 has alongitudinally extending lug 230 to engage in a slot on the engine part,and has a leaf spring 23,1 secured to its side by screw bolt 232 andprovided with an inwardly projecting end portion 233 passing throughaperture 234 for engaging a shoulder or groove or aperture on theadjacent part that is inserted in the bore 229.

A headed pin 235 is mounted in a bore 236, with its head 237 ybelow theleaf spring 231 in a counterbore 238. Thus the spring keeps the pin inplace; and the protruding end 239 of the pin may be pressed to releasethe rod in bore 229.

The other end lof the cylindrical rod 228 has a cylindrical bore 240,containing a live, resilient rubber bushing 241, which is provided witha laterally extending flange 242 engaging the end of rod 228.

Resilient bushing 241 has a bore 243 receiving the reduced rod portion244 Iwith a tight iit; and the rod portion 244 is an integral part ofhinge member 200, which has an annular shoulder 245 engaging theresilient ange 242.

'The parts are held in assembly by a screw bolt 232, which passesthrough a bore 246 in the rod 228 and is threaded into the bore 247.

Screw bolt 232 has its shank 248 surrounded by a live, resilient rubbersleeve 249, which is located in a bore 250 in the hinge member 200, andalso extends to the sides of bore 240. Thus the hinge member 200 isseparated from the part 228 without metal to metal contact; andvibration will not be transmitted to the handpiece from the enginemechanism, being absorbed by the rubber 241 and 24.

lThe present handpiece is adapted to be used with various attachments,one of which is exemplified in FIG. 9, showing a high speed contra angleattachment. This figure shows another sheath 91u, the right end of whichis similar to the sheath 91, previously described.

This sheath 91a is quickly attachable and quickly detachable from therest of the handpiece shown in FIG. 1 by substituting for it the sheath91.

Sheath 91a has its bore 121 provided with internal threads 251 forreceiving the lthreaded reduced portion 252 of the contra angleattachment 253. This attachment has the grooved and knurled lands 254 onits outer sur- Iface and is provided with an end bore 255, which formsan extension of the bore 121 of sheath 91a.

The attachment 253 has an annular shoulder 256- seating against the end257 of the sheath 91a; and it has a bearing bore 258 in its opposite endfor rotatably supporting a shaft 259.

Shaft 259 supports a driven member 174 at its right end (FIG. 9), whichcomprises a cylindrical body 260, having a bore 261 to receive the shaft259. A pin, riveted in the bore and the shaft, secures the driven member174 on the end of the shaft.

Bore 255 has an annular end surface 263 engaged by thrust surface 264 ondriven member 174. Driven member 4174 has longitudinally projecting lugs170 and 17111 ofthe same length as the lugs 170 and 171 in FIG. 2. Theselugs have the radially extending sides and beveled ends and occupy onlya portion of the periphery of the cylindrical -body 260. Asdistinguished from lugs 170 and 171, which have radial edges 145, thelugs 170e, 17,111 are wider in a radial direction and thinner in aperipheral direction, with parallel sides a.

The lugs and 171 can be seen in FIG. 9, located between lugs '17011 and171g, with a loose connection. Thus the spindle of the handpiece withits lugs 170 and 171 is adapted to drive the shaft 259 by theirengagement with the lugs 171m and 17in.

There is sumcient looseness between the parts of this drive so thatvibration of the universal joint structure is substantially eliminated;and it is found that the contra angle shaft 259 may be driven at a highspeed with a minimum amount of vibration when this kind of drive isemployed. Y

Referring to FIG. ll, this is a modiiication showing the spindlesupporting tube 68a when it is equipped with a spindle 45a mounted onball bearings at this end.

AThe tube 68a has a bore 12101 and a counterbore 265 atits end. Thecounterbore 265 is adapted to receive the ball bearing outer races 256with a tight frictional t; and this assembly includes two inner races267 and a multiplicity of balls 268 between the races. The inner raceshave an inner bore 270 iitting about the spindle 45a. The bore 272 isthreadedto receive the threaded thrust collar 275.

This assembly will fit in the lsame place in the handpiece 20 or FIG. l,wherey the tube 68 and spindle 45 is located; but it is mounted withball bearings instead of roller bearings.

The driving attachment 253 has its .shaft extending through a reducedportion 278 and provided with a gear 279 pinned to the shaft at 280, andhaving tapered end teeth. These engage similar teeth on a gear 281,forming a part of a contra angle 282 or part ofan attachment for packingand hammering amalgam into a cavity.

Referring now to FIGS. 17-20, inclusive, these figures show graphicallythe results accomplished by the use of the present improved handpiecesat high speeds at from 12,000 r.p.m. to 25,000 r.p.m. or more. I

FIG. 17 shows the time in minutes indicated on the ordinate plottedagainst r.p.m. indicated on the abscissa to show the reduction inminutes time which is accomplished by use of higher speeds in full crownpreparations. This curve shows that at 6,000 r.p.m. it took slightlyunder-forty minutes to prepare for a full crown, While at speeds of over20,000 r.p.m. it took about ten minutes.

FIG. 18 shows a similar curve on surface preparations and a similarreduction in the time required when high K trated in FIGS. 34-38 herein;and the ball bearing assembliesv are mounted in a different manner toreduce the number of parts and the number of machine operations and topermit the entire spindle assemblyto be removed for cleaning, as shownin FIG. 26, with the ball bearings mounted thereon. Y

In this modification similar parts bear similar numerals; and the sheath91 is similar in construction to that previously described, beingrotatably mounted upon the tube 6,8, which is a tubular extension of theelbow bearing housing 36 carried by the elbow 2S.

The rotatable sheath 91 has an enlarged boreV at its left end forreceiving the tapered nose portion 136,

Y which has a frictional iit in the end of the sheath 91' and has acontinuation of thebore 121 in the sheath, being rotatably mounted uponthe tube 68.

'In this modiication the tube 68 is provided with a smooth bore 67 Vforslidably receiving `the outer race of the ball bearing assembly Y35i),the inner race of which is frictionally and fixedly mounted on thespindle 45.

The Vspindle 45 has` an .outer cylindrical surface 143 and a reducedcylindrical portionll'hterminating at an annular shoulder 351, againstwhich the inner race 352 is seated; and the inner race 352 has a tightfrictional iit on the reduced portion 141.

Referring to'FIGS. 34-38, these are views showing the details ofconstruction of the ball bearings, which are preferably used at bothends of the handpiece instead of the roller bea-rings 12.Il and thebalibearings 49 disclosed in FIG. l.

The ball bearing assembly 35@ includes an outer race 353 and an innerrace 352. The outer race has an outer cylindrical surface 354 and aninner cylindrical surface n 355 and plane ends. The inner cylindricalsurface 35'5 ha the ball groove 356, which is continuous and withoutyfilling openings and formed on a radius larger than the radius of theballs 357. This gives the balls single point contact in the racegrooves. f

The ball bearing assembly is provided With a lesser complement of ballsthan is necessary toiill the grooves so that theballs are spaced equallyfrom each other out of contact with Veach other. The balls are held inthis position by the plastic ball retainer 36%), shownin eleva-y tion inFIG. 35.

The ball retainer 3653 comprisesy a short nylon tube, the endsv of whichterminate inside the ends of the races; and the internal and externaldiametersy are such that there is a clearance between the ballV retainer360 and each of the races.

The ball retainer 350 has a cylindrical bore 361 for each of the balls;and the bore is slightly larger than the ball diameter. Each ballsupporting bore 361 opens at one side into a parallel Walledl slot 362,which is slightly narrower than the ball diameter, so that'the slots 362may be forced over the balls until the balls are lodged in the bores361, as shown in FIG. 34. I Th races and balls are-assembled by locatingthe racesy eccentrically with respectto eachother so that they areVlooseness to tbe removed lwith the spindle.

of the slots 362,'which holds the retainer on the balls,-

the balls in turn being retained by the grooves.

The retainer prevents the balls from striking each other and permits thelubrication of the ball bearings by the use of air containing alubricant mist or by im= mersing the bearing in liquid lubricant.

A similar ball bearing is used `at the rear end of the handpiece, wherethe ball bearing assemblyis indicated by the numeral 363 (FIG. 25). .Y YY Thepresent modiiication is similar in construction to FIG. 1 at therear endwhere the bearing housing 36 carries the forwardly extendingtube 68, which rotatablyV supports the sheathV 91. The sheath 91comprises two sections; and the rear section comprises a sleeve 72iixedly secured to the front section by the rotatable joint structure32, shown in FIG. l. l

The rear section V72, has a radially extending annular flange 77engaging an annular shoulder at 76 and secured by means of a threadedcollar 7() which has the threads Y '66 for securement to the housing36,` but permitting free rotation of thev sheath assembly 91, S2, 72.

The spindle 143 extends through the rear section of the handpece, Whereit has anannular shoulder 364 and a reduced end portion 365.

The inner race of the ball bearing assembly 363 engages the shoulder364,`and in turn is engaged by the metal sleeve 46, whichV is engagedby thepulley 140. The pulley 14) has the bore receiving the reduced end 365 ofthe spindle and is provided with a key and key-Way The chuck rod extendsthrough a sleeve,` 369 inside Y the spindle 4S to a point near the toolend of the handpiece, Where it has a threaded portion ,370' in athreaded bore 371 and a cylindrical head 372 for engaging the chuckfollower k373, which has a conical recessf374 en gaging the collet, 375.Y

The collet has slots 117 uin each of its'ends `and hasaV conical end 376engaging Vin a conical recess 377 whereby the collet may be contractedupon its central bore (not All theV shown) for clamping the shank of atool. details of the chuck may besubstantially as described with respectto FIG. l.

The outer race of the ball Y'bearing assemblyr363`is engaged in a lbore378 in the housing 36 with sui'licient race engages an annular shoulder37and is secured by .threaded collar 389, which vhas a land 381 engagingthe outer race, but has a clearance 332 with respect to the inner raceand with respect to sleeve 46. Y

, ri'he spindle and both ball bearing assemblies. 35!V and 363 may beremoved with the collark 381) and the pulley l-tl and chuck rod 367A bymerely unscrewing the collar 389 so that the spindle assembly, as shownin FIG. 26,

may be removed and cleaned and sterilized. l

Referring. to. FIGS. 27 and 28, Vthese are views showing the details ofa ball bearing contra angle attachment which may be attached tothephandpiece of FIG. 2 1 or FIG. 24, after the manner shown in FIG. 22.This contra angle attachment includes an elbow 383 having a l threadedbore 384 adapted to receive the Vthreadederid 385 of the short`attachment sleeve of FIG. 30 or of the longer attachmentv sleeve 3136of FIG. 29. f j

The elbowl 383 hasV a'bore 387 at an obtuse angle large enough toreceive the toothed gear388 and provided with an aperture 389v to whicha plastic hose may be attached to supplyA the contra angle"l withlubricant Vin theform of a`- mist carried by air. The ,elbowY has athreaded bore 399 for attachment lto the contra angle sleeve 391, lwhichhas a threaded end 392. Y

The contra angle sleeve 391 has aV through bore 393 communicating with acounterbore 394, which provides an annular shoulder y39/5 for engagingthe outer race of the ball bearing assembly 396. 1 Y Y The outer All theball bearings employed in the handpiece and attachments and contra angleare preferably of the type Shown in FIGS. 34-38, with spaced balls and aball retainer holding the balls in a continuous groove without fillingslots.

The outer race of the ball bearing assembly 396 is seated against theshoulder 395 in the counterbore 394 and may be frictionally heldtherein, while `the inner race may be frictionally mounted on the shaft397 and confined against removal by the gear 398, which is pinned to theShaft and adapted to engage gear 388.,

The sleeve 391 has an annular shoulder 399 engaging the end of elbow 333and is provided at its other end with a similar threaded portion 460adapted to be received in the threaded bore 491 in the contra angle head492.

In this case the sleeve 391 has an annular shoulder at 403 clamping aplate 454 against the annular shoulder 4il5 on the head, the platehaving an aperture to receive the threaded end 499. The plate 494 has alateral extension 465 (FiG. 28) having a bore for receiving the twin airand water pipes 496, 497, which are lbrazed in the extension 40S andheld thereby, with nozzle ends 468 and 499 directed toward a toolcarried by the contra angle.

The dii/erging ends 41u, 4H of the tubes are provided with the flexibleplastic air `and water hoses (not shown).

The threaded plug 493* has a counterbore 412 for frictionally receivingthe outer race of the ball bearing assembly 413; and the inner race isagain monuted on the end of shaft 397, where it is held by the balls andretainer and by the gear 414 thatv is pinned to the shaft.

The contra angle head 462 has a bore 415'extending at right angles tothe bore 4G and provided with an annular shoulder 416 at its upper endfor engaging the outer race of ball bearing assembly 417.

A sleeve 418 acts as a spacer at the outer races of ball bearingassemblies 417 and 419; and the race 419 is engaged by a threaded plug42@ in a threaded bore 421; but there is a clearance at 422 between plug429 and the inner race.

The shaft 423 comprises a hollow tube having an intei-nal bore 424 withan inwardly extending lug 425 for engaging a flattened portion on a toolshank. A pivoted lever 426 is pivoted on screw 427 and swings in a slot42S to bring a laterally open slot 429 into a groove in the tool shankto retain the tool shank in the shaft bore 424. The shaft 423 has areduced portion receiving at each end the inner races against annularshoulders; and the races may be xedly secured on the shaft, which has albevel gear 436 engaging bevel gear 431 on shaft 397.

The inner races of ball bearing assemblies 417 and 419 have a tightfrictional tit on the tubular shaft 423; and the sleeve 418 is cut awayat one side toward the right in FIG. 27 to clear the bevel gear 434. Thethreaded plug 420 has a clearance about the shaft 423 so that the shaftmay rotate freely with the inner races.

Referring to FIG. 29, this attachment is known as the long sleeveattachment, in which a long shaft 436 has a threaded bore 437 forattachment to a threaded end portion 438 on a relatively short attachingsleeve 439. Sheath 436 corresponds to the nose section 91 of the sheathin FIG. 24 and may be attached to the handpiece after the removal ofsheath section 91 by rotating thevattachment sleeve S2.

The spindle 45 is indicated in dotted lines and is provided with theaxially projecting lugs 179, 171, only one which is seen in FlG. 29.

The body of sleeve 439 has a through bore 449 serving as a bearing for ashaft 441, which has the gear 388 pinned on onecnd and a driving fitting174 pinned on the lother end. The driving tting has the axially eX-tending lugs 17Go and 71cz, previously described, be-

14 tween which the lugs 179 and 171 on `the spindle 45 are received.

The present driving connection differs from that shown in FIG. 9 in thatthe lugs 170er, 171a #are surrounded by a coil spring 442, which tendsto maintain their alignment and improves the smooth running qualities ofthe joint.'

Spring 442 has an inwardly turned radial end 443 anchored in acomplementary bore in the tting 174 so that the spring 442 alwaysremains on the coupling member 174 when the sleeve 435 and the spindleare removed.

Referring to FIG. 30, this is an example of the short sleeve attachment,which can be directly attached to the handpiece of FIG. 24. This shortsleeve attachment comprises a tapered body 444, which has the reducedthreaded end 335 receivable in the threaded portion 384 of the contraangle attachment of FIG. 27.

The body comprises a solid portion 445 having a through 4bore 446forming a bearing for the shaft 447, to which gear 448 is pinned. Theshaft is held in its bearing by a thrust collar 449, having a tightfrictional tit on the shaft and engaging thebase 450 of a bore 451,which communicates with a tapered bore 452 that ts on the tapered nose186.

The body 444 terminates in an annular collar 453, which has an axiallyextending slot 454 separated by adjacent resilient portions 455 and 456,which are separated from the body by a peripheral slot 457.

The collar 453 fits about the body of the sheath 91, while the taperedportion 452 fits on the nose 186; and the shaft 447 projects into thechuck collet 375, where it is gripped.

The slot 454 fits on either side of a lug 455 (FIG. 24) carried by thenose 186.

Referring to FIG. 31, this is a fragmentary sectional view of a contraangle high speed attachment, into which there is a three to one ratiobetween the driven gear 459 and the driving gear 460.

The body 461 of this attachment corresponds to the sleeve 391 of FIG. 27and has a bore 462 forming a bearing for a'shaft 463, to which thedriven gear 459 is pinned at 464. The body 461 terminates in a threadedportion 455 adapted to be received in the threaded end 466 of `anenlarged elbow housing 467. l

The elbow housing 467 has a tapered portion 453 extending at an obtuseangle at its threaded bore 449, which receives `a threaded plug 47 tl,terminating in a sleeve 471. Sleeve 471 has la bearing for the shaft473, to which the small gear 469 is pinned.

Sleeve 471 corresponds to the sleeve 439 of the long attachment or thesleeve 444 of the short attachment of FIGURES 29 and 3G. By means ofthistriple speed gear drive the contra angle may be driven at threetimes the rate of rotation of the spindle 45. Referring to FIGS. 32 and33, these are fragmentary views of the ridler pulleys assembly, showinga modification of FIG. l2. ris similar to FIG. l2 except that the newconstruction includes improved arrangements for lubrication. V The idlerpulleys are mounted on the same arms 2.2 and 200 of FIG. l2; and thehinged body 194 is pivotally secured to said body* by screw bolts 474yand 475. The

hinged body 194 has a through shaft 476 secured in a bore 477 by a setscrew 478.

The set screw 478 has a bore 479' for the entrance of lubricant.

The shaft 476 has a through bore 480, which is threaded4 In thismodification the construction' race for the rollers 48o, which are heldinthe pulley by a pair of Washers 437, 458 for each pulley, the Washersengaging the ends of the rollers 486, and being in turn engaged by thethreaded collars 48S', which are threaded into threaded end portions ofeach bore 485.

Each roller assembly is lubricated by lubricant coming from the bore 43uthrough radial bores 491i.`

The pulley guards 481, 482 have their convex ends' provided -Withovalkidney shaped apertures 491, 492,

493 (PEG. 32) which are found to reduce the noise level and to effect acooler running of the idler pulley assembly.

The modilications which are shown in the new FIG- URES 2li-'36 includethe improvements not shown in the original parent application, Ser. No.494,607, of which this is a continuation-impart.

It Will thus be observed that I have invented improved dental handpiecesAadapted to be operated at speeds yof 25,000 R.P.M. and higher; andthese handpieces operate with a minimum amount of vibration and atlighter pressuresA and reduce `the time for cavity preparation to afraction of that required using the devices of the prior art,Whioh'could not Ybe rotated Iat such high speeds.

My improved handpieces may be-used with a plurality of interchangeableattachments, each of which is carried by a separate sheath in suchmanner that the'sheath and attachment may be released by merely turninga collar and pulling; and another attachment may be substituted by beingslid into the same place and secured by'V turning the collar. n

This permits the same handpiece structure to be used with a multiplicityof Vattachments,'each of which has its sheath quickly lattachable ordetachable from the rest of the handpiece.

While I have illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention; and I do Y not wish to be limited to the precise details ofconstruction f set forth, but desire to avail myself of all changesWithin lthe scope of the appended claims.

Having thus described my invention, VWhat. I claim as 4new and desire tosecure by Letters Patent of the United States, is:

1. In a high speed dental handpiece, the combination 'of a support withan elongated external sheath rotatably mounted on said support, atubular metal member in said sheath, antifriction bearings carried byone end of said tubular member, antifriction bearings carried by theotherv end of said tubular member, a spindle rotatably mounted in saidsheath in said antifriction bearings, said spindle being provided With apulley at one end and being proyvided with a driving connection at theVother end for driving dental tools, said driving connection being lo-Vcated inside said ishearth, and being in -alignment'with an laperturefor tool Shanks, said sheath being provided' intermediate its ends with`a separable joint, the major portion of the tool end of said sheathbeing quickly detachable, and means for Vlocking said quickly detachableportion of said sheath on the other portion of saidV sheath, said lattermeans comprising -a manually rotatable collar Vand a circumferentiallyextending open band carried by Y sheath assembly rotatably mounted onvsaid tube, saidv sheath -including a shorter end portion adjacentsaid'wrist joint, and a longer portion adjacent said chuck, said sheathhaving an opening in its end for insertion of tool Shanks h g Y n Yforms of toolends, a jointed rod for supporting said wrist l y into saidchuck, the parts of said sheath being separable joint, said jointed rodbeing provided adjacent its end with f so that thelonger portion of saidsheath. may be removed and any of -a plurality of similar elongatedsheath-portions may be substituted, carrying different forms of toolends, and rotatable means for locking said sheath por-j tions togethercomprising'an actuating collar land a rotating band under said collar,said band being open at one side for release of the longer portion ofsaidv sheath, and

said band being located in circumferential grooves extending about bothof said sheath portions.

3. In a multipurpose dental handpiece, the lcombination of a Wrist jointmember having an elongated tube carried thereby, a spindle rotatablymounted in saidtube and having a chuck at one end, said spindle alsoterminating in a pair of longitudinally extending drive lugs, a sheathassembly rotatably mounted on said tube, said sheath including a shorterend portion adjacent said Wrist joint, and Va longer portion adjacentsaid chuck, said sheath having an opening in its end for insertion oftooldshanks into said chuck, the parts of said sheath being separableVso that the longer portion of said sheath may be removed and any of aplurality of similar elongated sheath portions may be substituted,carrying dilerent forms of tool ends, and rotatable means" for lockingsaid sheath portions together comprising an actuating collar' and arotating band under said collar, saidband being open at oneV side forrelease of the longer portion of said sheath, and said band beinglocated in circumferential grooves extending about both of said sheathportions, one of said sheath portions having a longitudinally'extendingslot extending ybeyond said groove into vsaid lattersheath portion, and

the other of said sheath portions having a longitudinally extending lugformed with said groove and extending into said slot to prevent relativerotation betweenV said sheath portions.. Y

4. In a-multipurpose dental handpiece, the combination of a Wrist jointmember having an elongated tube carried thereby, a spindle rotatablymounted in said tube `and having a chuck at one end, said spindle alsoterminating in` a pair of longitudinally extending drive lugs, asheathassembly rotatably mounted on -said tube, said sheath including `ashorter end portion adjacent said Wrist joint, and a longer portionadjacent said chuck, said sheath having an opening in its end forinsertion of tool Shanks into said chuck, the parts of said sheath beingseparable so that the longer portion of said sheath maybe removed andany of a plurality of similar elongated'sheath por: tions may besubstituted, carrying dierent -forms of tool ends, said elongated tubebeing providedat its end'adjacent the tool end of said handpiece with anexternal race on its inside comprising a tubul-ar member having aninternal cylindrical surface and threaded internally at each of itsends, aplurality of rollers mounted against said cylindrical surface insaid race and engaging said spindle, and thrust collars threaded in eachend of said race and having a clearance with respect to'said spindle,said thrust collars limiting the axial movement of said rollers, each ofsaid thrust collars beinglprovided with an inwardly extending annularretaining tlange adjacent said spindle for extending over an axiallyextending part on each roller and preventing the rollers from droppingout of said race when the spindle is removed.

5. In a multipurpose dental handpiece, the combination of a wrist jointmember havingan elongated tube Vcarried thereby, a spindle rotatablymounted in said tube and having a chuck at one end, said spindle alsoterminatmg in a pair of longitudinally Vextending drivelugs, a shea/thassembly rotatably mounted on said tube,l said sheath including ashorter end portion adjacent said Wrist joint, and a longer portionadjacent ,said chuck, saidY sheath having an opening in its end -forinsertion of tool Shanks into said chuck,the parts Vof said sheathYbeing separable so that the longer portion ofV said sheath may beremoved and any of a plurality of similar elongated sheath portions Imaybe substituted, carrying different a secondy supporting Vrod carried by'the dental engine, and

17 l a resilient rubber non-metallic joint between said supporting rodand jointed rod for preventing transmission of vibration from one rod tothe other from engine to handpiece. Y

6. In a multipurpose dental handpiece, the combination of a Wrist jointmember having an elongated tube carried thereby, a spindle rotatablymounted in said tube and having a chuck at one end, said spindle alsoterminating in a pair of longitudinally extending drive lugs, a sheathassembly rotatably mounted on said tube, said sheath including a shorterend portion adjacent said wrist joint, and a longer portion adjacentsaid chuck, said sheath having an opening in its end for insertion oftool shanks into said chuck, the parts of said sheath being separable sothat the longer portion of said sheath may be removed and any of aplurality of similar elongated sheath portions may be substituted,carrying dierent forms of tool ends, a jointed rod for supporting saidwrist joint, said jointed rod being provided adjacent its end with asecond supporting rod carried by the dental engine, and a resilientrubber non-metallic joint between said supporting rod and jointed rodfor preventing transmission of vibration from one rod to the other fromengine to handpiece, said nonmetallic joint comprising a pair oftelescoping members forming part of said rods, and a resilient rubbersleeve between said telescoping members for preventing metallic contactbetween them.

7. In a dental handpiece, a supporting tube and a rotating spindlemounted in said tube, said spindle having an external Cylindricalsurface, andrsaid tube supporting a plurality of rollers for engagingsaid surface, an outer race located in a counterbore in said tube andhaving an inner cylindrical surface engaging said rollers, said outerrace being threaded internally at each of its ends, and a pair of thrustcollars engaging the ends of said race and having reduced threadedportions threaded in each end of said race for preventing said rollersfrom moving axially beyond said collars, said rollers each beingprovided with concavely formed axial points at each end, and an annularflange carried yby each of said thrust collars and located inwardly ofsaid points on said rollers but having a clearance with regard to saidpoints, said flange preventing the rollers from dropping out of saidrace when the spindle is removed.

8. A dental handpiece adapted to drive dental burs and to drive contraangles having a drive shaft like a dental bur, and adapted to driveother high speed contra angles, comprising a hollow spindle having anaxial opening at one end and provided with a collet chuck for graspingtool Shanks or driving pins of contra angles, said spindle also having apair of axially extending diametrically opposite drive lugs, and adental attachment cornprising a tubular metal body provided with athreaded portion for supporting a threaded contra angle and having adriving gear for driving the contra angle at its outer end, and at itsinner end a driven member with a pair of longitudinally extending spaceddriven lugs, said driven lugs and driving lugs interengaging and havinga loose driving connection for minimizing vibration of said handpiece,which is due to said driving connection.

9. ln a dental handpiece, the combination of a supporting wrist jointhaving an enlarged housing provided with an lelongated axially extendingtube, a ball bearing carried by said enlarged housing and rotatablysupporting one end of a spindle, a roller bearing carried by the otherend of said tube and rotatably supporting the other end of said spindle,a sheath rotatably mounted on said tube and covering said spindle andhaving an axial opening, and quickly attachable and detachable means forjoining together two parts of said sheath which are separable, one ofsaid sheath parts being removable for substitution of a similar parthaving a driven shaft with axially extending driven lugs, the saidspindle being provided at its end with axially extending driving lugshaving a loose driving connection with said driven lugs for transmittingthe rotation of said spindle to said shaft, said ducing to a minimumlateral vibration of the handpiece at said lugs, the said sheathincluding a shorter part adjacent the Wrist joint, and a longer partadjacent the tool end, said parts having complementary axial lugs andslots at the point of their juncture, and said lugs having aperipherally extending groove, and a rotating band open at one side formovement into grooves in both lugs to hold the sheath parts together orfor rotation out of the groove in one lug to release one part of thesheath from the other.

l0. In a dental handpiece, the combination of a supporting tube providedwith anti-friction bearings at each of its ends, a spindle rotatablyymounted in said antifriction bearings and having a driving endprojecting from said tube, said driving end being provided with a pairof axially extending lugs extending from the periphery of said spindleand Ihaving radial'driving surfaces, a sheath detachably mounted on saidtube, and a contra angle having a housing mounted on said sheath, saidcontra angle having a driven shaft for supporting the Shanks of toolsand having a driving shaft geared to said driven shaft, said drivingshaft lterminating in a driving couplinU similar `to the end of saidspindle and having a pair of axially extending lugs provided with radialdriving surfaces loosely engaging the driving lugs on the end of saidspindle, said driving and driven lugs having a peripheral clearancebetween them which is greater than the peripheral thickness of the lugs,the Said loosely engaging driving lugs eifecting a drive of said contraangle at high speed with a minimum of handpiece vibration.

ll. ln a dental handpiece, the combinationof asupporting tube providedwith anti-friction bearings atV each of its ends, a spindle rotatablymounted in said antifriction bearings and having a driving endprojecting from said tube, said driving end being provided with a pairof axially extending lugs extending fromy the periphery of said spindleand having radial driving surfaces, a sheath detachably mounted on saidtube, and a dental hammer having a housing secured to the end of saidsheath, the said dental hammer having a reciprocating sleeve forsupporting hammer tool shanks, and having a driven shaft provided with adog for hammering a ange on said sleeve, the said driven shaft beinggeared to a driving shaft, said driving shaft terminating adjacent theend of said spindle, with a pair of axially extending driving lugshaving radial driving surfaces loosely engaging .the driving lugs onsaid spindle, said driving lugs having a peripheral thickness which is asmall fraction of the'adjacent peripheral space beside the lugs, foreffecting a high speed drive of said dental hammer with a minimum amountof vibration.

l2. In a dental handpiece, the combination of a first sheath tube havinga driving spindle rotatably mounted in said tube, anti-friction bearingsin said tube rotatably mounting said spindle, the said spindle having atits free end a lirst pair of axially extending driving lugs with radialside surfaces on said lugs, a second sheath tube secured to the iirstsheath tube and a driven spindle rotatably mounted in said second sheathtube, said driven spindle lhaving a second pair of axially extendinglugs with radial side surfaces on said latter lugs, the said pairs oflugs being receivable in overlapping driving relation, said lugs in eachcase comprising an axial extension of the spindle carrying them, eachpair of lugs being separated radially by a spindle bore, and each lugbeing wider radially than its peripheral width, leaving a vacant spaceperipherally between the lugs on each spindle adapted to receive the-lugs of the other `spindle with a clearance between driving and drivenlugs peripherally which is wider than any of the lugs, for eiecting ahigh speed drive with a minimum amount of vibration.

13. ln a `dental handpiece, the combination of a iirst sheath having aperipherally grooved extension with an .xial groove in said extension,said axial groove transwith the-first-mentionedi peripheral groove, anda sliding Y rotatable band'in said first-mentioned groove and saidl bandhaving a .gap forpassing said axial-extension when the` band is rotatedto have its gaprregister with Vsaid 14. In`a dental handpiece, asupporting'sheath'hawng a threaded end and having a driving spindlerotatably mounted therein, and provided'at its end with axial drivinglugs, an extension secured to said sheath having a complementarythreaded end, andhaving a driven shaft mounted in a'bearing and providedat its driven end with axial driven lugs, said lugs having a peripheralclearance from each other at the overlapping portion of the driving anddriven lugs, which clearance is greater than the peripheralthicknessofthe lugs, providing a loose driving connection, reducing vibrationwhen driven at speedsin excess of 12,000 r.p.m. v

i l5.V A dentalrhandpiece according to claim 14, in which l the-saidextension has a threaded connection to a contra anglehousing containinga driven shaft connecting gears and a tool supporting shaft for arotatable bur.

16. A dental handpiece according to claim 14, in which the saidextension is provided with a threaded connection to a contra anglehou-sing having a driven shaft connecting gears and a reciprocabledental plugger shaft Yfor holding a dental piugger.

17. yA dental'handpiece adapted to drive dental burs andV also VdriveattachmentsV having axially projecting,

Y widely spread lugs on the end of the driven shaft, comprising ahandpiece having a sheathand a spindle rotatably mounted in said sheath,said spindle including a tubular part having a reduced portion mountedin roller bearings, said tubular part having a Vbore ending in Van innercone at its tool end, a split collet with a cone end to be contractedVby said inner cone to grip a bur shank, said tubular part having asmaller bore in its end leading to the collet interior, and having apair of widely spaced narrow axial lugs Von theend ofthe tubular part,and a taperedY housing 'for thetubular part, having, an end bore and aninner counterbore;

" 18. AIn an apparatus of the class described, a hollow bodyhaving anapertured end wall, a spindle extending through said end wall, anantifriction -bearing located within the body and including inner and'outer race means, the outer race means abutting said end wall, a fixedannular shoulder on the spindle engaging a front face of the inner racemeans, externally accessible means on Ythe Y spindle for engaging a rearface of the inner race meansV and thereby cooperative with saidannular'shoulder for Vagainst said hollow head. Y

19. An apparatus as in claim 18, in which the inner sheath structure hasan enlarged bore at its front end, and the bearing at the front end ofsaid inner sheath is of anti-V friction type and includes outer'racemeans tightly fitting said enlarged bore and abutting aV shoulder at theinner end of said enlarged boref Y 20. An apparatus as in claim 19,including a retainer secured Within theeinner sheath structure inengagement with the 'outer race means of the front antifrictionbearingfor maintaining the said bearing against said shoulder.

21. A dental handpiece comprising a rear bearing housing having anenlarged bore, and an inner annular shoulder surrounding a smaller bore,an antifriction Vbearing comprising an outer race, an inner race, androlling ele- Y the outer races are removably mounted in the housing andY as such for cleaning. Y Y

24; A dental handpiece arm assembly comprising a 2a ments, said outer'race being mounted insaid enlarged bore against said annular shoulder,threaded'means car- Yriedby'said housing and engaging the other end ofsaid; Y

outer race to secure the outer-.race in said/bearingjhousing,V a spindlehaving an annular shoulder engagingfthe Y.

forward end lof said inner race), a drive pull'eyifixedlyV mounted onsaid spindle, and a spacer tube between said pulley and the other end ofsaid inner race, van elongated Y` tubular member carried by said bearinghousing and extending forwardly about said spindle but spaced from fsaid spindle, a second antifriction bearing supporting therfV forwardend of said spindle in said tubular member and comprising Ya secondinner race, a second outerra'ce'and rolling elements, said second outerrace'being mounted'inY` a through bore in said tubular member, andsaid's'econdA Y' inner race being mounted on .the forward end of saidspindle.

22.Y A dental handpiece according to claim V21, in which n the saidhousing rotatably supports an outer sheath VYextending forwardly aboutsaid tubular member and afixed A' elbow on said housing, the rotatablesheath permittingA the elbow to ,hang downwardly when thersheath isheld*V in the hand. l

23. A dental handpiece according to claim 21, in which the inner racesare tightly mounted on the sheath, and

Vtubular members so that the spindle unit may be removed hinge platehaving a through bor-e, a tubular pulley shaft in said bore, a set screwthreaded in a bore in said plate engaging said shaft, and having alborein the set screwV communicating with the inside of said tubular shaft, apulley rotatably mounted on rollers on said shaft,a pair of roller`retainers threadedinto said pulley, Va washerfor retaining lubricant ateach end of the rollers,V a cap :screw threaded into the end of thetubular shaft, and' having aguard rim extending into proximity with thepulley, said shaft having a conduit extending from the inside of thetubular shaft to the rollers for distributing lubricant from said setscrew bore lto the rollers. Y

` 25. An assembly according to claim 24, in whichthe Yguard hasVentilating openings between thecap screwY and the guard rim for coolingthe assembly.

26. A long sleeve handpiece assembly comprising a dental handpiecehaving a sheath with a removable frontV section and a spindle with axialdriving lugs, a long replaceable tubular sleeve adapted to receive saidspindle,V

said sleeve having a solid end section containing an kaxial through boreforming -a bearing, a shaft in said bearing, havingra gear on its outerend and having/a driven-fitting on its inner end provided with drivenaxial lugs, meshing with the driving lugs of said spindle, and a coilspring having one end anchored in the driven fitting and surrounding thedriving and driven lugs to maintain their alignment. Y r

27. A short sleeve handpiece assembly comprising a Y dental handpiecehaving a front sheath section withl anose piece and a spindle with achuck, a tubular rnernber'hzu'f-V means for preventing its rotationrelative to said noseV 28. In anfapparatus of Vthe class described, ahollow body having a lthreaded cap thereon with an aperture in said cap,ajspindle extending through said cap and clearing said aperture, ananti-friction lbearing located within the body Y and including inner andouter race means, the outerV race means abutting Vthe inside, of saidcap, a fixed annularv shoulder on the spindle'engaging -a front face ofthe inner race means, externally accessible means on theY spindle for fengaging a rear face of the inner race means and thereby cooperativewith said collar for clamping the antifriction devices upon the spindle,an inner sheath structure conneeted to said hollow head and extendingforwardly therefrom along a part of Vthe length of the spindle, abearing at the front end of the inner sheath for supporting the spindle,an outer structure sur-rounding the inner sheath structure and extendingtherebeyfmd for providing a stationary nose -for lthe handpiece, andremovable means for pressing the outer structure against said hollowhead.

References Cited in the file or" this patent UNITED STATES PATENTSCarlson Apr. 26, Toelcke Nov. 24, Thau-Jensen Jan. 19, Dietrich Feb. 15,Zay et al. Apr. 3,

